Why do some teeth decay more quickly than others?

Decay: It's the Pits -- and the Fissures

Take a look in the way back of your mouth or just feel along the tops of your back teeth with your tongue. Rather than being smooth or pointed on top like the teeth up front, these larger teeth have ridges and grooves known as pits and fissures.

While these pits and fissures are essential in chewing food -- just try to imagine grinding up a bite of meat with those pointy front teeth -- they also make back teeth the most prone of the permanent teeth to decay and cavities. Often toothbrush bristles can be too big to fit into pits and fissures, allowing bacteria to form, which produces the acid that causes tooth decay [source: Mayo Clinic]

So, what can you do to keep cavities from forming in the ridges and grooves of your back teeth? The answer starts with good health and dental care in children -- and can begin as soon as the premolars, or six-year-old molars, come in.

Throughout our lives, from age 6 to 106, in the developed world, the most common factor that leads to cavities or decay is the bacteria that sticks around on teeth after eating sugary snacks or drinking sugary drinks and then is not removed completely [source: Mayo Clinic].

Among other tool, dental sealants help dentists keep food out of these troublesome spots Dentists apply these smooth plastic coatings easily and painlessly to the tops of back teeth to seal the fissured surface, blocking cavity-causing bacteria [source: Colgate].

Dental sealants are most often added to children's teeth as soon as the premolars erupt completely through the gums. The other molars get sealant as they come in later in childhood [source: Colgate].

Less commonly, other teeth with grooves or pits in them may get sealant. They also can be applied on the deep grooves or fissures of teeth in adults if the teeth do not have fillings in them [source: Colgate].

So, what can you do to keep the teeth you know and love, including those cavity-prone molars, healthy? The next page looks at ways to combat tooth decay.